The invention relates to a power supply arrangement with a first controlled power output, a second controlled output, and a controlled backup output which is connected to several read/write memories of a computer, and in which the read/write memories can be switched over to a stand-by mode in case of a power failure and connected to a backup battery.
Power supply arrangements for computers which supply several controlled output voltages are commercially available. In these arrangements, the computer components are connected by means of a d.c. (direct current) bus with a controlled power output of the power supply arrangement. The dynamic read/write memories of the computer are connected via a backup bus with still another controlled output, which in case of a power failure is supplied by a backup battery. The read/write memories require a direct voltage of 5 V (volts) and a current of 3.5 A (amperes) for active operation and of 1.5 A in the stand-by mode. This power supply to the read/write memories is managed either by adjusting an existing voltage of the power supply arrangement or by means of a voltage source expressly designed for this purpose. If an existing voltage is to be adjusted, then this voltage must be adjusted to the voltage values of the read/write memories by means of a controllable switch, a smoothing device, a current/voltage regulating circuit, and a control circuit for the switch. Since the buffering runs low, the control circuit of the controllable switch is of the discrete component design. The drawback of such an adjustment of an existing voltage or of a power supply expressly constructed for the read/write memories is that the power supply arrangement then requires an extensive number of components and thus occupies a large amount of space.
There is a need to improve the power supply arrangement of the above-mentioned type in such a way as to reduce the number of components required as well as to reduce the attendant bulk.